DE1941473A1 - Character generator - Google Patents

Description

Dipl "-Phys. Leo Thul '*'

Patent Attorney "1 ^ A1A71

Stuttgart - Feuerbach f VH ι HI 3 Kurz Strasse 8

G, M, Gardner 8

STANDARD TELEPHONES AND CABLES LIMITED, 19o Strand, London W.C. 2 / England

Character generator

The invention relates to a character generator for control a one-dimensional! multi-track recording head for printing units with partial recording of the characters in the mosaic grid.

The font generators used up to now for the aforementioned purposes see a diode matrix, a ferrite core memory or a waffle iron memory to store the available characters before.

In contrast, the present invention proposes a character generator before, which is characterized by a multi-stage shift register in which the available Characters, subdivided into serial codes in sections, in stock and are constantly circulating that means are provided which indicate which character series code is currently at the output of the shift register is available for evaluation and that a code comparator is provided, which the record compares pending characters with the cyclically offered character string and causes the transfer from the memory, if there is a match of the compared characters has been established. ■ · '

00 9808 / 15Λ3 "L

August 12, 1989 - 2 -. ·}

vHy / ha.

G.M, Gardner 8th

On the basis of an exemplary embodiment, the invention is in connection explained in more detail below with the drawings,

Figure 1 shows in the form of a block diagram a font · character generator according to the invention,

FIG. 2 shows part of a cyclically operating code generator represents which, in the character generator of the "Figure 1 is used.

Figure 3 illustrates another part of the code generator, such as it is used in the circuit according to FIG. 1,

Figure 4 shows an alternative arrangement to the one shown in Figure 3 _:

Figure S. shows a modified form of a part of the generator system of Figure 1,

FIG. 6 shows part of the block diagram of FIG

with an arrangement for varying the character • distances.

FIG. 7 shows part of the block diagram from FIG. 1 with a different arrangement for varying the character spacing, '

The one in FIG. 1 is shown schematically in the form of a Brock circuit diagram character generator shown is a for example, version that allows a two-half-twenty-lane Recording head 16 (corresponding to twenty

000071 SU

G.K. Gardner 8 -3-. '

Characters) at a rate of up to 50,000 characters per Second to operate »so that the connection to a cathode ray display is also conceivable · This recording speed corresponds to five hundred lines at 200 characters per second «Or, in other words, if, as in the present example, the recording head 16 Part of an electrographic printing or display device is, in which the characters formed by it in the form of charge images on the surface of a printing drum 17 are applied. This is set in rotation by a motor 18, which has a paper feed of approx Meters per second at 6 lines per two and a half centimeters.

There is also a possibility of providing the system with a facsimile reception logic with halftoning, which ^{operates at the same * 1} paper speed as in the section described above.

The basis of the present character generator is one cyclically operating code generator 8, which is a shift register includes, which works either with a preselection method or on the feedback path. When using suitable Feedback factors can be used by the shift register to generate Code cycles are used which have a length which corresponds to the number of storage elements of the register.

009808/154

G.M. Gardner 8 --M- -

In the present case it is important to provide a buffer memory which can hold at least one complete line of characters if repeated retransmission is to be avoided. If only one character memory, it is necessary that-during the movement phase of the printing drum 17 to replenish a line spacing · diesel engine but this leads to limitations in collaboration of the printer to a computer system and requires for high throughput _A speed between the printer and the central system "

This difficulty is illustrated by that illustrated in FIG Character generator largely overcome! at the two Line memories 2 and 3 are provided, which are so arranged are that in each case one of the memories has a receive logic 1 is filled in from the data source, while the information located in the other memory, e.g. by printing it out be evaluated on a paper tape

It should be noted, however, that this character generator is not limited to the use of only two line memories, but any number of line memories desired be used. For certain applications it may be necessary be to provide more than two line memories, e.g. if the Character generator together with an electrographic one Printing unit and / or a display device is used which has a printing drum which rotates at a relatively high speed. In this case, a facility

009808/1643

G.M. Gardner β - 5 -

which only "uses two line memories, the time between the Receipt of the message signal and the printing of the last line of characters are not long enough for the printing drum to be connected to the To stop the end of the message flow so that it is necessary to to increase the storage capacity of the facility | by a larger number of line memories is provided. The additional Storage capacity is to be selected so that the time, which between receipt of the message end signal and its generation of the last character of the message passes. sufficiently long is to stop the drum at the right moment. All incoming data, e.g. from a tape reader or via a Long-distance line arrive, receive logic 1, which forwards the processed characters to line memory 2 or 3, where these are stored line by line. Two line memories are necessary because at input A data in the time a « during which the previously received information, e.g. can be evaluated by printing.

In addition, the receiving logic 1 recognizes the beginning and the end of a * ¹ every message transmission and shows this as well as other function codes by signaling the printer and tuell. the data sources to «.

The received data determined by the receive logic 1 from the received data Fairy tale form. is fed to a shift pulse generator 5, Output is connected to the code generator 8. The two

00 9808/1543

Line memories 2 and 3 change their function under the control a switching stage 4, this can be seen from Figure 1, in which, for example, the memory is via a switch SW 1 is connected to input A, i.e. via the contact position 1 of this switch and the contact position 1 of the switch SW 3 with reception logic 1. At the same time, memory 2 is in the contact division via a switch SW 2 connected to a code comparator 9, which ultimately the Controls character formation. The switching stage 4 causes the switches SW 1 and SW 2 to be switched over together when the stored line of one line memory is printed out and the other line memory with the next to be printed Line is filled. When this occurs, the line- Memory 2 is connected to the receive logic 1 and the line memory 3 is connected to the code comparator 9.

It should be noted that the switches shown in FIG SW 1 and SW 2 in practice as electronic switching units are trained

The recording head i ^ß forms the characters on the surface of a printing drum 17 in the form of a charge image which is built up in dots. To record the point-like charge image on the drum surface, a series of processes are necessary to form a line. The top "dot row of the first character must be formed _t followed by the top of the second character, etc first" After the Schreiben'der th row above, the last -Zeiche _XXS% d "of the twentieth character hV

G.M. Gardner 8-7-1941 A 73

for the above-mentioned recording head, the drum 17 be rotated by the motor 18 so far that the recording the second row of dots below the first becomes possible This process must be used to form a dot matrix of, for example, a maximum of 22o χ 22 points for the 22 rows of points to be repeated to form a line with twenty characters from this matrix.

In one possible embodiment of the character generator a character transmission takes place through a continuously circulating code generator 8, which is a preselection shift register and which is designed according to FIG.

The number of storage levels is determined by the number of marking points of the complete repertoire of the character generator is determined. I.e. for characters of one matrix size from 2o χ Io points with a reserve of fifty alphanumeric Characters were required ten thousand levels of memory be. It is clear that a single shift register can fulfill this task as well as a number of several, parallel shift registers can be used when working with a reduced clock rate.

The N stages of the shift register, which in practice are designed as bistable multivibrators, are shown in FIG symbolizes the blocks Sl, S2, S3 ... SN. Each of the N levels is on the one hand with a shift pulse source, i.e. with the output of the shift pulse generator 5 connected, ■ 'elcher by the pulse train determines the operating cycle of the shift register, and

.009808 / 1543 - ρ -

BATH ORIGINAL

GM _Gardner;! - fr. »" - ,. ". . ','.

on the other hand with a pulse source, which with the beginning of a Character formation process an adjustment pulse on each of the N levels let get, which lets the levels toggle either in the "1" or "0" state »As soon as an N bit more extensive Serial code at the input of the Nth level $ i.e. the. Stage SN occurs, the output signal of this stage is given back to the input of the first stage Sl, so that the N bit comprehensive Serial code is continuously available at the output «

■ - j.

In the example given, the shift register comprises ten thousand Storage levels so that a ten thousand bit serial code is available at the output of the last level of the register * stands. Each of the fifty characters is replaced by a two hundred bit

comprehensive section of this serial code. Each A two hundred bit serial code representing a character can be further subdivided by dividing each of the 20 rows of dots by ten, consecutive bits is represented. These rows of points will continue to be referred to as character segments *

The air output of the shift register is connected to the inputs of a recording head control circuit ',' 10, via which respectively a section of very pen. is selected. For example, assume that the speed of the character string is a Characters per second, i.e. a new one per second Character arrives at input A and in the same clock sequence from the Line memory is read out · In this case the complete Set of fifty alphanumeric characters within a se-

m 9 -

0 09808 / TS A3

would be available for access by the control circuit 10 stand. This means that the clock pulse train of the shift pulse generator 5 of the required rotational speed in the shoot ·? must correspond to a register of 10,000 bits per second.

So that the section of the respective character intended for recording can pass the control circuit 10, a character reference code counter belonging to the code generator 8 is provided, which is designed so that, at the quoted 1 character / sec speed, a cyclic sequence for each of the fifty reserve characters is provided 6-bit parallel code generated. This series of fifty character codes are sent ¹ in cyclic sequence to a code comparator 9 every time a visual character section is to be selected Section of the serial code comprising bits and representing a specific character occurs at the input of the control circuit 10, the corresponding 6-bit parallel code is present at the input of the code comparator 9.

A character section counter 19 is assigned to the code comparator 9, which with a line storage capacity of twenty alphanumeric characters is designed so that it sends a sequence of twenty control pulses per second to the code comparator

there, through which a section of characters can be selected each time »This sequence of control impulses, each of which

- 10 *

ÖÖ98O0 / 1E43

G »Μ. Gardner 8 - 10 -

Remove ten bits from the 10,000-bit serial code in the: Location is »are chronized with the named serial code in such a way that that always at the time when the one representing a sign 200 bit comprehensive code section at the input of the control circuit is available, always in synchronism with the 10-bit sections of the 200 bit range is always one of the twenty Control impulses to the code comparator 9 and this section mark.

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In order to ensure the required data sequence to the recording head 16, the characters must be read out one after the other from the line memory and entered into the code comparator 9, to which on the other hand twenty control pulses per second are fed from the counter 19 ₉ whereby the phase position between this pulse sequence and the 10,000 bit - production code changes every twenty seconds by an amount which is equal to the time interval of ten bits of the serial code is "This facilitates the formation of a character line of twenty characters on the surface Trömme _β as: was described!.

From what has been described above, it follows that each from the line memory in the Cod ever the same 9 adopted Characters are compared / is compared with each of the fifty character codes, which are fed to the code comparator 9 by the code generator 8 * When determining the correct code, the from , Line segment counter 19 resulting from the control pulse

Code comparator 9 to the control circuit 10 j whereby ten bits i ... "of the IQeOOO bit serial code" whichever section is desired

. of the selected character, the ·, To pass control circuit Io as a lo-bit parallel code, in order then to amplifier stages 12 via storage elements 11 to get. In association with a 2oxll selection matrix in form a diode decoder 13 and a character counter 15 are used to control the two hundred and twenty tracks of the Recording head 16 ".

The control of the individual write head tracks takes place one after the other, by the switching steps summarized in the character counter 15 can be effectively controlled by appropriate series pulses. The recording speed can be increased as a result by controlling the switching stages all at the same time. In this case, the need for the cache would be reduced 11 superfluous, which lead to a reduction in costs can. However, a character counter is then required, which is provided with eleven-track switching steps »

In the operating state, pulses arrive one after the other via the twenty output lines of the character counter 15 on the selection * - * - matrix 13 after they have been brought to the required value by an amplifier stage Vi. Each of the twenty pulses selects the information that passes through the control circuit and represents a section of one of the twenty characters of a line. This ensures that the assignment in the two hundred and twenty input lines of the recording head 25 takes place in the predetermined sequence. '*.

009808/1543. _12th

G.M.Gardner 8-12 «. 1 94 T4.73.-. ■ "'

To ensure this, it is necessary according to Figure 1 • that the character counter 15 is synchronized with the character portion counter, in such a way that the character counter 15 his. Counting cycle in coincidence, with the twenty readout pulses, which over each of the twenty output lines of the decoder 13 are fed to the code comparator 9 * As a result • It is ensured that of the distributed over twenty lines two hundred and twenty possible recording points each the are marked on the circumference of the printing drum 17, soft to Formation of the twenty characters to be recorded on a line required are"

When receiving the facsimile transmission, the above-described, multiple transcoding is not required, · in this case the information pulses are fed to a register 2o via the input line B, via which they are sent directly to the control circuit Get io. The rest of the process then takes place entirely in the the manner described above. It is also possible within a Transmitting from normal step code reception to facsimile reception by simply switching from input A to input B. · «■ -

The shift register shown in Figure 2 is one in the. Carry out practice in integrated circuit technology · An economic loan However, the solution to such a Cödeerzeittgung offers Using a feedback shift register (feddback shift register) or M-sequence generator »

009808/15 * 3 - 13 '- ■

; β.Μ. Gardner's - 13 - 194Η73

Such a generator, which is part of the code gene · - . Rators 8 of Figure 1 can form is shown in a simplified form in Figure 3. As can be seen from this illustration, the generator consists of an N-stage shift register, represented by the interconnected blocks S1, S2 «*» SN, to which a module 2-gate circuit 6 is assigned. These gates can be connected to different levels of the register. The outputs are connected to the steps, while the outputs of the gates are connected to other steps of the register, so that a single loop but also multiple loops can be formed.

The functional details of this type of register will not be discussed as it can be assumed that these are widely known. However, the following articles should be noted: ■

(a) "Generation and Properties of Maximum-Length Sequencies"

by WiDrTi Davies in the June, July and August editions 1966 of the trade journal "Control".

(b) "Generation of delayed replicas of maximum-length * linear

binary sequences "by S» H. Tsao, in Proc. I.E.E », Volume 111, No. November 11, 196H,. ·

From the above it can be seen that if suitable feedback functions are used, the register can be used to: . · .. to generate a code cycle »the length of which is well over the number \

. 'The storage levels of the chain can thus be looked at with correct

ÜÖ98Ö8 / 1S43 * ^: ^

G.M, Gardner 8 - 1Λ - 1941 Λ 73

• Selection of the feedback functions for this shift register be caused to generate the required character image sequence etc, in the manner described above, where now far we-

. Less memory levels are required. " than when executing of the shift register according to Figure 2 »

As before, the register is prepended to ensure a correct start and any number can be used in parallel * ' to facilitate control of the character generator. -

Instead of the sliding elements of the M-sequence generator vöreinzustellen that derived from the character memory font character data can the generator are fed directly, for example in einer.Weise as FIG M- ₈ shows where this is via a module 2 gate 7, wherein the generator is designed so that at the start it has a two hundred bit series code representing this character for each coded character

keeps available »The number of individual loops which are used to form this aoo-bit serial code in the M-Fölger generator is determined by the respective character code input so that the correct loop pattern for generating the selected character series is determined. It should be pointed out that the serial code output signal of the generator can comprise more than 2oo bits, but the generator would be designed so that the proper 2oo bit pattern can be fixed. ·; ■ "'■. - - . ..- ■■ - '■: ^■■;: · *''■■:'; ■■

980g / 1 S 4 3

} Since the character code taken from the line memory causes the control circuit Io to select the 20Q-bit serial code, it is necessary to modify the character generator system of FIG. 1 in accordance with FIG. In this modification, the code comparator eliminates 9 · The part of the Codegenratörs forming, character reference code counter is arranged for this system at a Zeilenepeicherkapazität of 'twenty alphanumeric characters ι that it comprises a series of twenty control pulses to each of _# the location indicated by the numbers 1 to 2o input lines the control circuit Io, with one of the control lines each being assigned to one of the twenty character segments.This series of control pulses, each of which is able to select ten bits from the two hundred bits of the range code *, is synchronized with the character sequence speed in such a way that each time with At the beginning of a new cycle of the twenty 20-bit serial code, the control circuit Io is influenced via the next line by one of the twenty control pulses in such a way that the required section of the currently pending character can pass the control circuit. Thus, the character reference code counter causes the cyclical supply of twenty control pulses with one in the above-described conditions. Speed of 1 pulse per second over each of the twenty input lines to the control circuit Io · This facilitates the formation of the line consisting of twenty characters on the drum surface in the manner described above. The phase position of the individual traffic pulse series is such that their time interval on adjacent lines is equal to the time interval of ten bits of the. ·

009808/1543

^; - 16 -

GVM. Gardners - 16 - IQA

2oo-bit serial code is

It should be noted that. The shift registers shown in Figures 2 to 4 can be replaced by a delay chain, which is provided with taps at suitable points ₍ which facilitate the necessary connections and the supply of suitable control, shift or feedback pulses * However, these arrangements work in the same way Way, wits the shift registers described above ·.. ·

For certain applications it may be important to have a line justification so that in the character generator Means must be provided to keep the distance between the to vary individual characters · In Figure 6 is a block diagram of a part of Figure 1 is shown in which. Middle -" are available to change the spacing between characters. With this arrangement, the code comparator 9 gives when it the consistency of the one taken from the line memory Character detects a control pulse from which identifies the selected character. This signal is fed to a width measuring device 21 in which this signal is converted and is passed on to the character counter 15 · This is in In the present case, designed so that it counts in small steps that are equal to the center line of the mosaic points. He .-does not count in fixed character segments, as is the case with the Device according to Figure 1 is the case. The width measuring device

009808/1543

ORIOINAL IMSPECTHD

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gives a signal which is a function of the width of the im Code comparator 9 represents the pending character on the Character counter 15 »

This is caused by an appropriate number of To peel further apart in order to transfer the character data to the corresponding traces of the recording head 1Λ This ensures that the desired distance between the signs are adhered to.

An alternative solution for varying the character spacing is shown in FIG. 7, which includes part of the block diagram of FIG. In this arrangement, the recording head distribution logic is controlled by the character itself, in that the parallel output signal of the control circuit 10, which in each case represents a character segment, also reaches a width measuring device 23 via corresponding lines, the output of which is connected to a character counter 15 A pulse generator 22 is assigned to the control circuit for 10 ^s

The task of the pulse generator 22 is darini after Selection and transmission of a character section by the Control circuit 10 to apply a series of pulses to this before the arrival of the next character which the remaining segments of the character in the form of a maximum parallel signal comprising ten bits can be read out. The total width of the character is the logical product of

G.M. Gardner 8 -18-. 19414/3

this output signal, which has a maximum of ten bits, and the preceding one corresponding to a character section Output signal. . "" '

This logical operation is carried out by the width measuring device 23 carried out. For this purpose, the output of the device is 23 connected to the counter 15, which corresponds to the marker point distances counts in incremental steps and not in fixed character widths, as is the case with the system of FIG.

Via the output of the device 23, the counter 15 is caused to take a suitable number of incremental steps to increase the characters pending in partial form correspond to the appropriate traces of the Recording head Iß, taking into account the intended space between characters it to map. There is another possibility to read out the remaining segments of the selected character. In this In this case, the task is taken over by the character section counter 19 in conjunction with the code comparator 9, so that the pulse generator 22 does not more is needed. In this arrangement, the counter 19 in connection with the code comparator 9 after the evaluation of the pending character section through the circuit 10 and before read-out pulses when the following character arrives, which in series or parallel form to the control circuit 10 and cause the reading of the remaining character sections which are used for the evaluation of the width measuring device 23 are fed. It should be noted that this type of

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G »M. Gardner 8 - 19 -

. Distance variation also in the system shown in FIG Can be used · * '.

The above-described devices for varying the character spacing are designed so that the spacing of the characters within words are always the same "

In contrast, the inter-word spaces are a separate code signal. assigned, which, fed to the width measuring device, a corresponding continuation of the counting device by the same Number of incremental steps causes »In order to achieve greater controllability of the line adjustment, it is necessary that the inter-word code information about the required width of the distance which the width measuring device contains. able to evaluate. This can be achieved by ensuring that a word coming from the line memory is used as a space character such is recognized and fed directly to the width measuring device, which forms an output signal which is a function of the Represents the width of the word spacing. This signal is sent to the counter supplied, which is due to a corresponding increment " further counts the number of steps, as a result of which this distance is assigned to the tracks of the recording head »Zn this In this case, the line memory must be directly accessible from the width measuring device *.

The character generators described above can be designed so that the use of magnetic recording

heads is possible, as described in the German patent applications P 17 7 "f 318.9, P 17 74 525," * and P 17 7 * f 552.7. '

009808 / 15A3 - 20 -

β. * »! * Gardner δ - 2ο -, 1141473

In these applications, the blocks 11 to 15 are not required and the control circuit Io must be designed in such a way that it supplies an N-bit serial code on the output side, which is fed to the control logic assigned to the recording heads S2 $ »U and ... P 17 m 552» 7 the N-bit * serial code is converted into a pulse sequence of uniform polarity and decreasing size (amplitude), with each of these pulses having at least one other pulse of opposite polarity and smaller * size (Amplitude) follows »

Auchdie arrangements adopted for varying the Zeichenäbstandes may find use _t In this case, when using the above-mentioned magnetic recording heads is the output of the width measuring the input of the recording head control logic to connect. The latter must be designed in such a way that between the supply of successive series output signals to the recording heads there is a delay "which is sufficient" to generate the desired spacing between the adjacent characters.

Instead of building up a line of text in rows in the manner described above, it can be advantageous for certain applications to create a complete character during a logical operation instead of a section of this character » In the measurement case, the line memories, including the switching stage, are not required, but the receiving stage can be connected directly to the system on the output side. the

6.M * Gardner 8 -21 -

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Counting and gate circuits are designed that way! that they. in a similar manner} as the corresponding circuits operate in the previously described examples, except that (the present _t sample based) twenty sections are fed sequentially to the recording head instead of one single Zeiohenabschnittes, resulting in the generation of a complete character result in "The In the examples described above for FIGS. 6 and 7, the means for varying the character spacing can be used in the same way in this embodiment, with the one exception that the pulse generator is not required in the embodiment according to FIG read all twenty character segments via the control circuit Io and thus pass also to the width measuring device 23, which in turn is designed so that _r. it forms a logical product of the individual values, which provides information about the width of the character in the form of an output signal.

1 claim

4 sheets. Drawings with 7 figures

Claims (1)

G.Μ »Gardner 8 -22 - , - Pat β η t a η a ρ r u c. H Character generator for controlling a one-dimensional, multi-track recording head for printing units with section-wise recording of characters in a mosaic grid, characterized by a multi-level shift register (S1 to SN), in which the characters available are stored, divided into serial codes in sections and constantly circulate that means are provided which indicate which character series code is currently available for evaluation at the output of the shift register (Sl to SN) and that a code comparator (9) is provided, which cyclically displays the character pending for recording with the compares offered character string and causes the transfer from the memory if a match of the compared characters has been found,. August 12, 196?
vHy / ha ORiGiMAL INÖFEÖTED